The present invention relates to electronic devices for detecting a cardiac arrhythmia and in particular to a device providing improved patient mobility and reliable long-term monitoring.
The human heart normally beats anywhere from 60 to 80 beats per minute when a person is at rest. Diagnosis of cardiac arrhythmias normally requires that a qualified professional review an electrocardiograph (ECG) in which the electrical impulses from the heart are recorded and displayed in chart form. The electrical impulses are measured by electrodes attached at a number of locations to the patient's chest. Certain episodes of cardiac arrhythmias, although serious, can be unnoticed by the patient. For example, it is desirable that chronic atrial fibrillation be treated within 48 hours of its onset.
One possible solution is the use of a “cardiac event recorder”, a portable ECG recording device carried by the patient and communicating with electrodes worn under the patient's clothing and adhesively attached to the patient's skin. Such recorders may provide algorithms for monitoring the ECG signal and may report to the users, for example, that atrial fibrillation has begun. Recorders of this type may also record a rolling “window” of ECG data using solid state computer memory. In this latter case, the recorded ECG data may be transmitted over phone lines, the Internet, or the like for review by a qualified physician.
Unfortunately, the cardiac event recorder is not a practical tool for providing a warning of the onset of certain cardiac arrhythmias that can occur unexpectedly at any time in later life. The need for the patient to carry the cardiac event monitor about during the day and the continuous attachment of electrodes is impractical for long term monitoring that may span decades.
What is therefore needed is a less cumbersome, and more patient-friendly, apparatus and method for detecting cardiac arrhythmias than currently achieved.